7.4 A pretimed four-timing-stage signal has critical lane group flow rates for the first three timing stages of 200, 187, and 210 veh/h (saturation flow rates are 1800 veh/h/ln for all timing stages). The lost time is known to be 4 seconds for each timing stage. If the cycle length is 60 seconds, what is the estimated effective green time of the fourth timing stage?

16 seconds

Explanation:

Given:

C = 60

L = 4 seconds each = 4*4 =16

In this problem, the first 3 timing stages are given as:

200, 187, and 210 veh/h.

We are to find the estimated effective green time of the fourth timing stage. The formula for the estimated effective green time is:

Let's first find the fourth stage critical lane group ratio , using the formula:

Solving for , we have:

Let's also calculate the volume capacity ratio X,

X = 0.704

For the the estimated effective green time of the fourth timing stage, we have:

Substituting figures in the equation, we now have:

15.78 ≈ 16 seconds

The estimated effective green time of the fourth timing stage is 16 seconds

answer:

a

explanation: